What is the difference between...

[Charlie]

TV and CATV? And why? I'm referring to the setting on modern sets and vcr's. I use a VCR/DVD combo as my cable box on my sets, but just for the hell of it, I connected a splitter to my CM roundie and connected the cable directly to it. Being that a roundie isn't "cable ready", the channels are different on the UHF dial. Cable channel 77 will be found somewhere near 29 on the 1966 UHF tuner... cable channel 78 somewhere near UHF 30. I have to say "somewhere near" because the UHF tuner is continuous. A little lower down the dial... let's say cable channel 20... won't be tunable on the UHF dial.

So what's the reason for this? Why not have cable channels the same on a digital tuner and an old fashioned tuner?